1. Field of the Invention
The present invention relates generally to vibrator tool assemblies and, in one possible particular embodiment, to a vibrator tool with rotating engagement surfaces or camming surfaces which repeatably engage each other to produce vibrations for advancing bottom hole assemblies in oil and gas operations.
2. Description of the Prior Related Art
Oil and gas operators have continually found new methods of incorporating coiled tubing into various rig applications. Coiled tubing often has advantages over a conventional rig and drillstring, in that coiled tubing units can be less expensive and quicker to set up than conventional drilling rigs.
One major problem to both conventional and coiled tubing rigs is the ability to push tubing further into a wellbore under certain drilling conditions. Generally, drillers rely on the weight of the drillstring to counteract the frictional forces generated between the wellbore and drillstring. Once a certain depth is reached, or certain formations are drilled into, or at certain angles of the wellbore, the weight of the drill string is not sufficient to overcome the friction of the drill string to move the drill string downwardly as drilling continues. This tends to be especially true in coiled tubing operations, because coiled tubing cannot be rotated at the surface to overcome or reduce the friction the drill string with respect to the wellbore. Another significant factor is that coiled tubing tends to be more flexible and lighter compared to traditional drill pipe. As a result, coiled tubing may experience increased drag problems in the wellbore as compared with traditional drill pipe and is more prone to become lodged in the wellbore. This effect can become exacerbated in deviated wells and those with horizontal sections, where movement of pipe by the injector rig at the surface does not result in additional movement of the coiled tubing string into the wellbore. Furthermore, coiled tubing is more likely to stick in the wellbore based on the coiled design and spooled storage, which can create a spiral effect that may increase the number of sticking points inside the wellbore.
Various tools and methods have been utilized to deal with this problem, including vibrating tools, jars, tractors, centralizers, and pulsators. Thus, many designs have been utilized. While such tools have been utilized successfully, the forces created thereby are not necessarily efficient in utilizing the energy created thereby. Accordingly, the present invention will be appreciated by those of skill in the art.